Molpro is a comprehensive system of ab initio programs for advanced molecular electronic structure calculations, designed and maintained by H.-J. Werner and P. J. Knowles, and containing contributions from many other authors. It comprises efficient and well parallelized programs for standard computational chemistry applications, such as DFT with a large choice of functionals, as well as state-of-the art high-level coupled-cluster and multi-reference wave function methods. 

Electronically excited states can be treated using MCSCF/CASSCF, CASPT2, MRCI, or FCI methods, or by response methods such as TDDFT, CC2, and EOM-CCSD. There are many modules for computing molecular properties, geometry optimization, calculation of harmonic and anharmonic vibrational frequencies, and further wave function analysis. Analytical energy gradients are available for DFT, HF, MP2, MP2-F12, CCSD, CCSD-F12, DCSD, QCISD, QCISD(T), CASSCF, and CASPT2. Density fitting (DF or RI) approximations can speed up DFT and MP2 calculations with large basis sets by orders of magnitude, and explicitly correlated methods [MP2-F12, CCSD(T)-F12, CASPT2-F12, MRCI-F12] minimize basis set incompleteness errors to yield near CBS quality results with triple-zeta basis sets. Combined with local approximations and efficient parallelizations, high-level methods [PNO-LMP2-F12, PNO-LCCSD(T)-F12] can be be applied to large molecules of chemical interest, yielding unprecedented accuracy (for a recent review see WIREs Comput Mol Sci. 2018, e1371). Furthermore, WF-in-DFT embedding or QM/MM methods can be used to extend the applicability of ab initio methods to large systems of chemical or biochemical interest. The following two reviews summarise with examples the capabilities of the package.

H.-J. Werner, P. J. Knowles, G. Knizia, F. R. Manby and M. Schütz, WIREs Comput Mol Sci 2, 242-253 (2012), doi:10.1002/wcms.82.

Hans-Joachim Werner, Peter J. Knowles, Frederick R. Manby, Joshua A. Black, Klaus Doll, Andreas Heßelmann, Daniel Kats, Andreas Köhn, Tatiana Korona, David A. Kreplin, Qianli Ma, Thomas F. Miller, III, Alexander Mitrushchenkov, Kirk A. Peterson, Iakov Polyak, Guntram Rauhut, and Marat Sibaev J. Chem. Phys. 152, 144107 (2020). doi:10.1063/5.0005081

Molpro is very easy to use for standard applications, but also includes many advanced options for expert applications. It runs under UNIX/Linux (2.6.32 kernel onwards) and OS-X (Mountain Lion onwards). Molpro can also be used as a platform for development.

News

Introductory licence discounts are available in the period 1/10/2023 to 30/11/2023 to anyone who has not held a Molpro licence in the last 6 months. 20% will be discounted from the licence fee for the first year of any non-commercial group or site licence, and a 12-month licence for gmolpro will be provided without charge.

Molpro version 2023.2 has been released in September 2023. It contains new features and improvements, and the changes are summarised here. Any feedback regarding improvements of this version will be appreciated.

Version 2.1.0 of the graphical user interface gmolpro is available since October 2022.

gmolpro is based on PQSMol.
With gmolpro, molecules can be built, and optionally be optimised based on force-fields.
Basic Molpro inputs can be very quickly generated. Sensible basis sets and input parameters are suggested.
Outputs from Molpro calculations set up with gmolpro, as well as output files from general input files can be visualised.
Output files (xml files) with several optimisations, frequency calculations, or even different molecules within one xml file can be handled. Start from the brown window, open the orbital window, and then select and load an orbital set. A corresponding optimisation or vibrational modes may now be displayed.
Orbitals with all angular momenta implemented in Molpro (s, p, d, f, g, h, i) may be quickly visualised.

gmolpro has been found very useful for teaching. It was much appreciated in computational chemistry classes at Stuttgart University. A separate licence is required.

Molpro 2015 and older versions are no longer supported.